Method for charging compositions, including a volatile propellant in pressure-tight containers



March v1954 o. M.- M BEAN ETAL 2,671,590

METHOD FOR CHARGING COMPOSITIONS. INCLUDING A VOLATILE PROPELLANT IN PRESSURE-TIGHT CONTAINERS Filed Dec. 8, 1949 INVENTORS D. M McBean ATTORNEYS including volatile -liquids, into pressure-tight containers.

Pea-med Mar. 9, 1954 METHOD FOR CHARGING COMPOSITIONS, INCLUDING A VOLATILE PROPELLANT IN PRESSURE-TIGHT CONTAINERS Douglas M. McBean, Rochester, N. Y., and Leo J. De Costa, Rutherford, N. J assignors, by mesne assignments, to Cart er Products, Inc., New

York, N. Y., a corporation of Maryland Application December 8, 1949, Serial No. 131,801 1 Claim. (01. 226-100) 1 This invention relates to the filling of fluids. propellants and aqueous In the packaging of materials including volatile propellants in pressure-tight containers, it has heretofore been customary to fill and close the container at atmospheric pressure, keeping the temperature of the materials to be packaged below a temperature at which the vapor pressure of the propellant i greater than the prevailing atmospheric pressure. packaged comprises or includes water or an aqueous solution or suspension, filling at low temperature is unsatisfactory because the temperature required to maintain the useful propellants in When the product to be liquid phase at atmospheric pressure is below the freezing temperature of the product or the water or aqueous solution therein. Thus, in filling at temperatures low enough to keep the useful propellants in liquid phase the product freezes and mixing of the product and the propellant is prevented. The container must therefore be subsequently heated and agitated in order that a proper mixing of the product and propellant be accomplished. This procedure is unsatisfactory both because of the time involved in accomplishing mixing by heating and agitating the container and because of the fact that, despite the heating and agitation, a satisfactory mixing is not uniformly accomplished.

By a volatile propellant we mean a compound having a vapor pressure appreciably above atmospheric pressure at normal room temperature. A number of such compounds are disclosed in co-pending application Serial No. 125,032, filed on November 2, 1949. Such compounds may be used and are satisfactory for propelling a liquid product of the type contemplated by this invention from its container.

It is the object of the present invention to provide an improved and economical method forcharging an aqueous product and a volatile propellant into a pressure-tight container without resorting to refrigeration and without resorting to the procedure set forth above for mixing the contents of the filled container subsequent to the filling operation. In general our improved method comprises the steps of introducing a measured charge of volatile propellant in liquid phase into a charging chamber, connecting the charging chamber to a packaging container having a measured charge of aqueous product therein and supplying to the charging chamber propellant in gaseous phase at a constant pressure above thevapor pressure of the liquidpropellant at the prevailing temperature, preferably room temperature, whereby all of the charge of liquid propellant i forced from the charging chamber 1 2 into the packaging container and the filling passages leading to the interior of the packaging container are cleared of liquid propellant.

For a more detailed description of the method of our invention, reference may be made to the accompanying drawing in which the single figure diagrammatically sets forth, in elevation and partly in section, one type of apparatus by which the method may be accomplished. Y

In the drawing a typical packaging and pressure-tight container is illustrated in section as having a body portion l and a suitably attached concave bottom wall 2. An outlet valve is sultably secured in an opening in the top wall of the can by a pressure-tight seal or connection. The valve shown comprises a tube 3 having an inturned flange 4 at its inner end which forms a valve seat. A valve plug 5, carried by a valve stem 6, is resiliently held in engagement with the valve seat 4 by a spring 1 which is compressed between the flange I and a stop 8 struck from the stem 6. Within the can is contained an aqueous liquid product 9 which will comprise approximately to per cent of thecontents of the filled packaging container. Such an aqueous product may be of th type disclosed in the copending application Serial No. 125,032, referred to above. A tube III of suitable material is fitted over the lower end of tube 3 within the can or packaging container and extends to a point near the juncture of the side and bottom walls I and 2 or the container. Such a positioning of the lower end of tube l0 assures expulsion of substantially all of the contents of the filled can when it is used.

A charging chamber ll, having a tube-like outlet I! at its lower end in which there is a valve I3, is located above the can or packaging container. A gasket [4 is supported at the lower end of outlet I2 beyond valve I3, the lower surface of the gasket being adapted to receive the upper edge of tube 3 of the container in a pressure-tight connection. A spider I5 is secured to the inner lower end of outlet l2 and has depending from it a valve-operating member IO, the lower end of which is adapted to engage the upper end of valve stem 6 when tube 3 01' the can is brought into engagement with the gasket ll. The gasket I4 is provided, on its lower surface, with a bevelled recess I1 surrounding and concentric with its central opening to assure a proper seating of the tube on the gasket so that valve-operating member IE will engage valve stem 6 to open the valve when tube 3 is seated on the gasket.

One satisfactory means for bringing the packaging container into position so that its valve tube 3 is connected to the outlet II of the charg- \ing chamber, through gasket I4, is a table ll. The table It, on which the container may be placed, is movable up and down by means of a ydraulic lift or other typ f pp rt.

a'supply container l9 for liquid propellant 1 is" connected to the charging chamber I I through a conduit 2| having therein a valve 22,101 111- stance'a check valve, a metering device 23, and a conduit 24 also having therein a valve 25, for example a check valve. The metering device 2! comprises a cylinder and a reciprocable piston 25 adapted to be reciprocated by a piston rod 21. When piston 25 is retracted in the cylinder. check valve 22 opens and a measured quantity of liquid propellant enters the cylinder. When the piston II is urged forward in the cylinder, check valve it closes and check valve 25 opens, permitting the flow. of the measured quantity of the liquid propellant to the charging chamber II.

A cylinder or container 29 of propellant is provided with a' valve 29 and pressure gauge 30 on its outlet fixture ll'and is connected to the upper end of charging chamber I I through condul't 32 in which there is a valve I3 for controllingthe flowjof gaseous propellant through the conduit. Cylinder .29 is supported in a liquid bath, 35. An electric heating element 86 extends into the liquid bath to heat the liquid and thereby the cylinder is and its contents. The circuit .of the heating element 38 is controlled by a switch," which is responsive to the temperature of the liquid bath by means of a thermocouple. or thermometer 38. By these means the contents of the container 28 may be kept at such temperatures that the pressure thereof may be maintained constant.

In using the above-described apparatus for carrying out the method of our invention, a supply of liquid propellant is maintained in container 19. The pressure acting upon the liquid pmpellant is the vapor pressure of the propellant at -the prevailing temperature. One suitable propellant that has been used has a vapor pressure of about 40 p. s. 1. gauge at room temperature, that is, at about 70 to 72 F. The propellant in gaseous phase, in cylinder or container 29, which may be either the same propellant as .is in container i9 or a suitably chosen similar one, in this case would be maintained at such a temperature that it would be under a pressure of approximately 40 to 80 p. s. i. gauge.

-The method of this invention, as carried out by the described apparatus, is as follows: Piston 20 is retracted and the metering cylinder is thereby filled with a measured quantity of liquid propellant II entering the cylinder through conduit 2| and check valve 22. The piston 20 is then moved forward in the cylinder, forcing the measured quantity of liquid propellant through the conduit 24 and valve 25 to the charging chamber ll, check valve 22 closing to prevent the return flow of propellant from the cylinder to container l9. With the charging chamber thus loaded with a measured quantity of liquid propellant. a container in which there has been introduced in any desired manner a measured quantity of aqueous product is connected to the lower end of outlet I! through gasket ll, the valve of the container being thereby opened. Valves II and 33, which have previously been closed. are then opened, preferably simultaneously but not necessarily so. Upon the openingof valve l3, propellant in gaseous phase enters the chamber ll above the liquid level of propellant II contained therein. The pressure of the propellant in gaseous phase being maintained by the liquid bath SI and heater II at a substantially higher pressure than the vapor pressure of the liquid propellant at the prevailing temperature, forces liquid propellant through valve l3. outlet l2, valve 3 of the container, and tube l0 thereof into the container at a point below the liquid level of the aqueous product therein. This mixes the propellant with the product during introduction of the propellant. Valves l3 and u are maintained open until the pressure of the mixture of aqueous product and liquid propellant in the packaging container is equal to the pressure of the propellant in gaseous phase supplied from the cylinder 29. The valves i3 and 33 are then closed and the container withdrawn from outlet II, the valve 5 in the container closing upon withdrawal of the container because of the pressure within the container. The pressure within the container thus is equal to the pressure of the gas propellant incylinder 28.

By this method containers may be rapidly filled to uniform pressures with uniform and intimately mixed quantities of aqueous products and volatile propellants. Additionally, by this method the only loss of propellant is of the small amount in gaseous phase remaining in the lower end of outlet tube It. If the propellant were introduced in liquid phase only, a considerably greater loss would occur because the volume of liquid propellant remaining in the filling or outlet tube 12 would represent a substantial portion of the charge of propellant introduced into the product container. the latter case a certain amount of liquid propellant might remain in the tube I of the container valve and in the upper-end of tube ll. thereby possibly causing the valve tofreeze closed and causing the first material subsequently propelled from the container'to be a shot made up primarily of liquid propellant.

The method of charging a pressure packaging container, having a measured charge of an aqueous product therein, with a volatile propellant which comprises the steps of introducing a measured charge of volatile propellant in liquid phase to a charging chamber under a precharging pressure at least as great as the vapor pressure of the propellant at the prevailing temperature, connecting the bottom of the charging chamber to the packaging container at a point below the level of the aqueous product therein, and simultaneously supplying to the charging chamber above the liquid level therein propellant in gaseous phase at a constant pressure above the precharging pressure whereby all of the charge of liquid propellant is forced into the packaging container, the propellant in gaseous phase being maintained at said constant pressure by being maintained at a temperature substantially above said prevailing temperature.

DOUGLAS M. McBEAN.

LE0 J. DE COSTA.

References Cited in the ille of this patent UNITED STATES PATENTS Number Name Date 1,895,177 Staley Jan. 24, 1933 1,989,030 Wade Jan. 22, 1935 2,462,642 Jacobson et a1 Feb. 22, 1949 2,505,799 Smith May, 2, 1950 2,505,800 Smith May 2. 1950 Alsoin 

